Elasmobranch responses to experimental warming, acidification, and oxygen loss—a meta-analysis

Despite the long evolutionary history of this group, the challenges brought by the Anthropocene have been inflicting an extensive pressure over sharks and their relatives. Overexploitation has been driving a worldwide decline in elasmobranch populations, and rapid environmental change, triggered by anthropogenic activities, may further test this group's resilience. In this context, we searched the literature for peer-reviewed studies featuring a sustained (>24 h) and controlled exposure of elasmobranch species to warming, acidification, and/or deoxygenation: three of the most pressing symptoms of change in the ocean. In a standardized comparative framework, we conducted an array of mixed-model meta-analyses (based on 368 control-treatment contrasts from 53 studies) to evaluate the effects of these factors and their combination as experimental treatments. We further compared these effects across different attributes (lineages, climates, lifestyles, reproductive modes, and life stages) and assessed the direction of impact over a comprehensive set of biological responses (survival, development, growth, aerobic metabolism, anaerobic metabolism, oxygen transport, feeding, behavior, acid-base status, thermal tolerance, hypoxia tolerance, and cell stress). Based on the present findings, warming appears as the most influential factor, with clear directional effects, namely decreasing development time and increasing aerobic metabolism, feeding, and thermal tolerance. While warming influence was pervasive across attributes, acidification effects appear to be more context-specific, with no perceivable directional trends across biological responses apart from the necessary to achieve acid-base balance. Meanwhile, despite its potential for steep impacts, deoxygenation has been the most neglected factor, with data paucity ultimately precluding sound conclusions. Likewise, the implementation of multi-factor treatments has been mostly restricted to the combination of warming and acidification, with effects approximately matching those of warming. Despite considerable progress over recent years, research regarding the impact of these drivers on elasmobranchs lags behind other taxa, with more research required to disentangle many of the observed effects. Given the current levels of extinction risk and the quick pace of global change, it is further crucial that we integrate the knowledge accumulated through different scientific approaches into a holistic perspective to better understand how this group may fare in a changing ocean

Spectrochemical analysis in blood plasma combined with subsequent chemometrics for fibromyalgia detection

Fibromyalgia is a rheumatologic condition characterized by multiple and chronic body pain, and other typical symptoms such as intense fatigue, anxiety and depression. It is a very complex disease where treatment is often made by non-medicated alternatives in order to alleviate symptoms and improve the patient’s quality of life. Herein, we propose a method to detect patients with fibromyalgia (n = 252, 126 controls and 126 patients with fibromyalgia) through the analysis of their blood plasma using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy in conjunction with chemometric techniques, hence, providing a low-cost, fast and accurate diagnostic approach. Different chemometric algorithms were tested to classify the spectral data; genetic algorithm with linear discriminant analysis (GA-LDA) achieved the best diagnostic results with a sensitivity of 89.5% in an external test set. The GA-LDA model identified 24 spectral wavenumbers responsible for class separation; amongst these, the Amide II (1,545 cm−1) and proteins (1,425 cm−1) were identified to be discriminant features. These results reinforce the potential of ATR-FTIR spectroscopy with multivariate analysis as a new tool to screen and detect patients with fibromyalgia in a fast, low-cost, non-destructive and minimally invasive fashion

Seahorses under a changing ocean: the impact of warming and acidification on the behaviour and physiology of a poor-swimming bony-armoured fish

Seahorses are currently facing great challenges in the wild, including habitat degradation and overexploitation, and how they will endure additional stress from rapid climate change has yet to be determined. Unlike most fishes, the poor swimming skills of seahorses, along with the ecological and biological constraints of their unique lifestyle, place great weight on their physiological ability to cope with climate changes. In the present study, we evaluate the effects of ocean warming (+4°C) and acidification (ΔpH = −0.5 units) on the physiological and behavioural ecology of adult temperate seahorses, Hippocampus guttulatus. Adult seahorses were found to be relatively well prepared to face future changes in ocean temperature, but not the combined effect of warming and acidification. Seahorse metabolism increased normally with warming, and behavioural and feeding responses were not significantly affected. However, during hypercapnia the seahorses exhibited signs of lethargy (i.e. reduced activity levels) combined with a reduction of feeding and ventilation rates. Nonetheless, metabolic rates were not significantly affected. Future ocean changes, particularly ocean acidification, may further threaten seahorse conservation, turning these charismatic fishes into important flagship species for global climate change issues

Multivariate classification techniques and mass spectrometry as a tool in the screening of patients with fibromyalgia

Abstract: Fibromyalgia is a rheumatological disorder that causes chronic pain and other symptomatic conditions such as depression and anxiety. Despite its relevance, the disease still presents a complex diagnosis where the doctor needs to have a correct clinical interpretation of the symptoms. In this context, it is valid to study tools that assist in the screening of this disease, using chemical work techniques such as mass spectroscopy. In this study, an analytical method is proposed to detect individuals with fibromyalgia (n = 20, 10 control samples and 10 samples with fibromyalgia) from blood plasma samples analyzed by mass spectrometry with paper spray ionization and subsequent multivariate classification of the spectral data (unsupervised and supervised), in addition to the treatment of selected variables with possible associations with metabolomics. Exploratory analysis with principal component analysis (PCA) and supervised analysis with successive projections algorithm with linear discriminant analysis (SPA-LDA) showed satisfactory results with 100% accuracy for sample prediction in both groups. This demonstrates that this combination of techniques can be used as a simple, reliable and fast tool in the development of clinical diagnosis of Fibromyalgia

Composition-solubility-structure relationships in calcium (alkali) aluminosilicate hydrate (C-(N,K-)A-S-H)

The interplay between the solubility, structure and chemical composition of calcium (alkali) aluminosilicate hydrate (C-(N,K-)A-S-H) equilibrated at 50 °C is investigated in this paper. The tobermorite-like C-(N,K-)A-S-H products are more crystalline in the presence of alkalis, and generally have larger basal spacings at lower Ca/Si ratios. Both Na and K are incorporated into the interlayer space of the C-(N,K-)A-S-H phases, with more alkali uptake observed at higher alkali and lower Ca content. No relationship between Al and alkali uptake is identified at the Al concentrations investigated (Al/Si ≤ 0.1). More stable C-(N,K-)A-S-H is formed at higher alkali content, but this factor is only significant in some samples with Ca/Si ratios ≤1. Shorter chain lengths are formed at higher alkali and Ca content, and cross-linking between (alumino)silicate chains in the tobermorite-like structure is greatly promoted by increasing alkali and Al concentrations. The calculated solubility products do not depend greatly on the mean chain length in C-(N,K-)A-S-H at a constant Ca/(Al + Si) ratio, or the Al/Si ratio in C-(N,K-)A-S-H. These results are important for understanding the chemical stability of C-(N,K-)A-S-H, which is a key phase formed in the majority of cements and concretes used worldwide

A thermodynamic model for C-(N-)A-S-H gel: CNASH_ss. Derivation and validation

The main reaction product in Ca-rich alkali-activated cements and hybrid Portland cement (PC)-based materials is a calcium (alkali) aluminosilicate hydrate (C-(N-)A-S-H) gel. Thermodynamic models without explicit definitions of structurally-incorporated Al species have been used in numerous past studies to describe this gel, but offer limited ability to simulate the chemistry of blended PC materials and alkali-activated cements. Here, a thermodynamic model for C-(N-)A-S-H gel is derived and parameterised to describe solubility data for the CaO–(Na2O,Al2O3)–SiO2–H2O systems and alkali-activated slag (AAS) cements, and chemical composition data for C-A-S-H gels. Simulated C-(N-)A-S-H gel densities and molar volumes are consistent with the corresponding values reported for AAS cements, meaning that the model can be used to describe chemical shrinkage in these materials. Therefore, this model can provide insight into the chemistry of AAS cements at advanced ages, which is important for understanding the long-term durability of these materials